html {
  width: 100%;
  height: 100%;
}

body {
  background-color: white;
  line-height: 1.4em;
  width: 730px;
  height: calc(100% - .5em);
  margin: 0px auto;
}

p {
  text-indent: 1em;
}

h1 {
  margin: 0 auto;
  padding: .5em 0;
  background-color: pink;
  font-size: 2em;
  line-height: 1em;
  text-align: center;
  width: 100%;
}

h2 {
  font-size: 2em;
  line-height: 40px;
  text-indent: .25em;
  border-bottom: 2px navy solid;
  border-left: 40px navy solid;
}

iframe {
  width: calc(100% - .25em);
  height: calc(100% - .25em);
  border: 0;
}

table {
  border-collapse: collapse;
  margin: 1em 0;
}

td {
  border: 1px solid;
  padding: .25em;
}

td>:first-child {
  margin-top: 0;
}

td>:last-child {
  margin-bottom: 0;
}

img {
  max-width: 100%;
}

.container_top {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: column;
}

.container_top>.content {
  flex-grow: 1;
}

.container_left {
  width: 100%;
  height: 100%;
  display: flex;
  flex-direction: row;
}

.container_left>.content {
  flex-grow: 1;
}

.copyright {
  margin: 0 1em;
  text-indent: 0em;
  color: gray;
  background: lightgray;
  font-size: 0.8em;
}

.illust {
  border: 4pt double navy;
  padding: 10px;
  margin: 20px 0px;
  width: auto;
}

@media screen and (max-width: 480px) {
  body {
    width: 100%;
  }

  h1 {
    padding: 5px;
    font-size: 2em;
  }
}